Five laboratories are carrying out research supported by this Program Project grant: 1) Genetic and biochemical control of replication, recombination and morphogenesis; lysogeny with the temperate phage P22 in S. typhimurium and the genetics of oncogenic transformation and latency by herpes simplex virus in mammalian cell culture; 2) Hormonal induction of tyrosine aminotransferase (TAT) in cultured rat hepatoma cells and the hormonal modulation of amino acid transport in cultured animal cells; 3) Biochemical genetics of abnormal human hemoglobins including biosynthesis studies; 4) Biochemical genetics of carbonic anhydrase and protein evolution including the expression of the isozymes in cultured cells; and 5) Genetic studies of histocompatibility antigens with special reference to the HL-A and H-2 systems of man and mouse. This coming year will see the initiation of a new area of research on the developmental genetics of differentiation alloantigens in mice and the biochemical genetics of spermatogenesis as a specific mammalian model of differentiation.